One of the most commonly prescribed antidepressants, sertraline, may begin to relieve some key symptoms of depression and anxiety within just two weeks, according to new research led by scientists at University College London (UCL).
The findings, published in the journal Nature Mental Health, provide new insights into how quickly and in what ways sertraline works.
Sertraline belongs to a group of medications called selective serotonin reuptake inhibitors (SSRIs), which are often used to treat both depression and anxiety.
While previous studies suggested it takes up to 12 weeks for noticeable improvements in depressive symptoms, this new analysis paints a more detailed picture.
The research team analyzed data from the PANDA trial, a large clinical study originally published in 2019. That trial showed that while sertraline improved anxiety symptoms and general mental health after six weeks, it didn’t seem to help depressive symptoms until week 12.
But this new analysis used a more detailed statistical method called network analysis to better understand how different symptoms changed during the course of treatment.
The new results suggest that some of the emotional symptoms of depression—like low mood, feelings of self-loathing, restlessness, and even suicidal thoughts—can actually begin to improve within just two weeks of starting sertraline. This is earlier than previously thought.
The analysis included 571 participants who had complete symptom-level data. All of them had mild to moderate depressive symptoms and were randomly assigned to receive either sertraline or a placebo for 12 weeks.
Those taking sertraline showed early emotional improvements, but also experienced some side effects—like reduced appetite, tiredness, low libido, and poor sleep. These side effects are common for antidepressants, but they can also overlap with physical symptoms of depression, making it harder to tell whether they are part of the condition or caused by the medication.
Lead author Dr. Giulia Piazza from UCL explained that this analysis gave a more complex view of how sertraline affects people. Instead of treating depression as a single condition, the researchers looked at individual symptoms, which can show up in different ways for different people.
For instance, someone might struggle with sadness and sleep problems, while another person might have anxiety and low self-worth.
She noted that symptoms often influence each other—poor sleep might reduce concentration, which in turn could affect self-esteem. By understanding how different symptoms react to medication, doctors can better tailor treatments.
The study also found that while emotional symptoms and anxiety improved over time, side effects such as sleep issues and low libido leveled off after about six weeks. This suggests that the negative physical effects of the drug may fade as the benefits continue to grow.
Co-author Professor Glyn Lewis, who led the original PANDA trial, said the findings strengthen support for prescribing sertraline to people with depression and anxiety. He emphasized that understanding which symptoms improve first can help patients and doctors make better decisions about treatment.
Professor Jean-Baptiste Pingault, another senior researcher on the study, added that these results show how important it is to look closely at specific symptoms when studying or developing psychiatric drugs. Knowing which symptoms respond first can also give patients hope that their treatment is starting to work, even if not all symptoms improve right away.
This research could help shape the future of mental health treatment by making it more personalized and responsive to individual patient experiences.
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The study is published in Nature Mental Health.
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